Recognition of Pachyarthron and Bossiella as Distinct Genera in the Corallinaceae, Subfamily Corallinoideae (Corallinales, Rhodophyta)

Abstract

Abstract New evidence supports recognition of both Pachyarthron and Bossiella as distinct genera within the Corallinaceae, subfamily Corallinoideae (Corallinales, Rhodophyta). Pachyarthron cretaceum, the type species of Pachyarthron, is confirmed to occur in Australia, and a new study of the designated lectotype of P. cretacea and of plants from Australia, Japan, Canada (British Columbia) and the United States (Alaska, Washington State) has shown that male conceptacles are produced both axially at branch tips and laterally on intergenicula. By contrast, only lateral conceptacles occur in Bossiella. Differences between Pachyarythron and Serraticardia & Marginisporum, the only genera of Corallinoideae known to produce both axial and lateral conceptacles, are outlined, and a comparison of and key to all genera of Corallinoideae are included. An emended generic description of Pachyarthron and an account of P. cretaceum are provided. Brief accounts of four infraspecific taxa never transferred into Pachyarthron...